The 499 is a logic converter designed to provide corrected logic type and/or pulse polarity for signals used to trigger events, to provide pulses to be counted, or to time specific events in timing or counting applications for nuclear, optical, chemical, or biological processes.

The 499 allows the user to convert between two of the most widely used logic types; fast negative NIM (negative 800 mV) and TTL (positive 2 V). In addition, the polarity can easily be switched. The 499 has a total of 16 channels of conversion.

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The upper half of the 499 provides eight channels of fast negative NIM to TTL logic conversion. These eight channels are divided into two, four channel segments that can be switched to Normal or Inverted outputs. The lower half of the module has eight channels of TTL to fast negative NIM logic conversion which are also divided into two, four channel segments that can be switched to Normal or Inverted outputs.

The maximum operating frequency for the NIM to TTL is 60 MHz and for the TTL to NIM is 40 MHz. All of the outputs are DC coupled with no duty-cycle limitations. The outputs are 50 Ω impedance and use 50 Ω cables for connection to 50 Ω loads. The total delay for any channel is less than 10 ns.